Roof bow



FIG. 1 is a front plan view of a roof bow showing my new design;

FIG. 2 is an end view of a roof bow;

FIG. 3 is a perspective view of a roof bow; and,

FIG. 4 is a top view of a roof bow.

In the drawings, the broken lines depict portions of the roof bow that form no part of the claimed design. 

The ornamental design for a roof bow, as shown and described. 